Unwanted cabin heat

M5guy · 07-26-2013, 05:41 AM

I'm getting unwanted heat in the cabin in my 86, which is compromising my AC. Sometimes a lot of heat. On the floor, in the defrost vents, but not the center vent or side vents.

The rotary knob between the seats is set to zero. I generally keep the four dash sliders set right in the middle year round, but no matter what position they are in, I'm getting heat. I checked the flapper valves with the car cold and they were in the no-heat, vent to atmosphere position.

I thought I was familiar with the heating system, but I must be doing something wrong, or the servo is going nuts when the car is running. Any thoughts?

JFairman · 07-26-2013, 05:54 AM

If the diverter valves aren't sealing anymore it would be easiest to just disconnect the hot air hose from the heat exchangers during summer and put them back on in winter.

mooney265 · mooney265's Garage

Quote:

Originally Posted by JFairman

If the diverter valves aren't sealing anymore it would be easiest to just disconnect the hot air hose from the heat exchangers during summer and put them back on in winter.

That's what I did...

M5guy · 07-26-2013, 06:22 AM

Ok, that's what I will do for the short term.

mooney265 · mooney265's Garage

Just disconnect from heat exchangers/headers and have them point at the ground.

Patrick 87 930 · Patrick 87 930's Garage

I have the same problem on my 87 cab. What's the long term fix?

mooney265 · mooney265's Garage

Quote:

Originally Posted by Patrick 87 930

I have the same problem on my 87 cab. What's the long term fix?

New Heater Boxes [2 of them]: 930 Heater flapper box help???

And, check your Control Cable Operation/Fastening... They can come unfastened thus causing the unit not to close properly...